i do not think so,since the next Olympic will be at London 2012.
The Commonwealth nations (Britain, Australia, Canada etc.) are regular medalists in equestrian, with their traditional rivals Germany. In London 2012, there's no chance for equestrian to be excluded.
In fact, as the cyclers and sailors are rolling in the gold for Britain in this Olympics, the performance of British equestrian team have been below expectation and subpar. They will dearly want to make amends in London 2012.